In some applications in which power is provided to high current loads, DC power cables are run in parallel between a power supply and the high current load. For example, parallel DC power cables may be used to supply power to plasma chambers that are used for manufacturing of semiconductor wafers, flat panel displays, compact disks, hard coatings, and other objects. To provide sufficient current to operate the plasma chamber, one known DC power supply comprising a DC plasma generator supplies current to two or three identical DC cables. These cables each carry up to 40 to 60 amperes at voltages up to 500 to 800 volts DC. The cables are typically coaxial power cables that connect to terminations at the DC plasma generator.
Overcurrent devices or circuits are known that are useful for protecting DC plasma generators, cables, and the plasma chamber in the event of an overload. However, overcurrent devices do not provide protection from some conditions. For example, overcurrent devices do not indicate or provide protection in the event of a poor cable connection or a break within a cable.